My 70 Malibu build

[chevymaher]

Sounds good. My frame used to be all pretty like that before I put the body on and did bodywork a while. Now it is a dusty mess.
Carb choice is just that a choice. Get what you like. As for size it depends on how you drive it. If your a animal like me a 750 is better, more top end. But if you drive like a normal person a 650 is better. Less hesitation when you stab the gas, more responsive. That motor would like either one tho.